U.S. patent application number 17/629085 was filed with the patent office on 2022-08-25 for nonaqueous electrolyte solution, nonaqueous electrolyte battery and compound.
This patent application is currently assigned to CENTRAL GLASS CO., LTD.. The applicant listed for this patent is CENTRAL GLASS CO., LTD.. Invention is credited to Ryota ESAKI, Susumu IWASAKI, Wataru KAWABATA, Masahiro MIURA, Takayoshi MORINAKA, Mikihiro TAKAHASHI, Ryosuke TERADA, Miyuki YAMAUCHI.
Application Number | 20220271340 17/629085 |
Document ID | / |
Family ID | |
Filed Date | 2022-08-25 |
United States Patent
Application |
20220271340 |
Kind Code |
A1 |
TERADA; Ryosuke ; et
al. |
August 25, 2022 |
NONAQUEOUS ELECTROLYTE SOLUTION, NONAQUEOUS ELECTROLYTE BATTERY AND
COMPOUND
Abstract
The present invention provides: a nonaqueous electrolyte
solution which is used in a nonaqueous electrolyte battery having a
low initial resistance value; and a compound which is contained in
this nonaqueous electrolyte solution. A nonaqueous electrolyte
solution according to the present invention contains a compound
represented by formula (1), a solute and a nonaqueous organic
solvent. In general formula (1), each of R.sup.1 and R.sup.2
represents PO(R.sub.f).sub.2 or SO.sub.2R.sub.f, and Rf represents,
for example, a fluorine atom; each of R.sup.3 and R.sup.4
represents, for example, a lithium ion, or alternatively R.sup.3
and R.sup.4 may form a ring structure together with a nitrogen atom
to which the moieties are bonded, and in this case, R.sup.3 and
R.sup.4 form an alkylene group in combination with each other; an
oxygen atom may be contained between carbon atom-carbon atom bonds
in the alkylene group; a side chain thereof may have an alkyl
group; and an arbitrary hydrogen atom in the alkyl group and the
alkylene group may be substituted by a fluorine atom.
Inventors: |
TERADA; Ryosuke; (Ube-shi,
Yamaguchi, JP) ; TAKAHASHI; Mikihiro; (Ube-shi,
Yamaguchi, JP) ; MORINAKA; Takayoshi; (Ube-shi,
Yamaguchi, JP) ; ESAKI; Ryota; (Sanyo-onoda-shi,
Yamaguchi, JP) ; IWASAKI; Susumu; (Ube-shi,
Yamaguchi, JP) ; YAMAUCHI; Miyuki; (Ube-shi,
Yamaguchi, JP) ; KAWABATA; Wataru; (Ube-shi,
Yamaguchi, JP) ; MIURA; Masahiro; (Ube-shi,
Yamaguchi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CENTRAL GLASS CO., LTD. |
Yamaguchi |
|
JP |
|
|
Assignee: |
CENTRAL GLASS CO., LTD.
Yamaguchi
JP
|
Appl. No.: |
17/629085 |
Filed: |
July 22, 2020 |
PCT Filed: |
July 22, 2020 |
PCT NO: |
PCT/JP2020/028526 |
371 Date: |
January 21, 2022 |
International
Class: |
H01M 10/0568 20060101
H01M010/0568; H01M 10/0525 20060101 H01M010/0525; H01M 10/0569
20060101 H01M010/0569 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2019 |
JP |
2019-136223 |
Claims
1. A nonaqueous electrolyte solution, comprising a compound
represented by the following general formula (1), a solute, and a
nonaqueous organic solvent: ##STR00008## [in the general formula
(1), R.sup.1 and R.sup.2 each independently represents
PO(R.sub.f).sub.2 or SO.sub.2R.sub.f, R.sub.fs each independently
represents a fluorine atom or a C1-4 linear or C3-4 branched
perfluoroalkyl group, R.sup.3 and R.sup.4 each independently
represents a hydrogen atom, a lithium ion, a sodium ion, a
potassium ion, or a C1-12 linear or C3-12 branched alkyl group,
wherein an oxygen atom may be included between the carbon atoms of
the carbon atom-carbon atom bond in the alkyl group, or R.sup.3 and
R.sup.4 form a ring structure together with the nitrogen atoms to
which they are bound, wherein R.sup.3 and R.sup.4, together with
each other, form an alkylene group; an oxygen atom may be included
between the carbon atoms of the carbon atom-carbon atom bond in the
alkylene group; a side chain thereof may have an alkyl group; and
an arbitrary hydrogen atom in the alkyl group and alkylene group
may be substituted by a fluorine atom, provided that in case where
R.sup.3 represents a lithium ion, a sodium ion or a potassium ion,
a bond of the nitrogen atom and R.sup.3 in the general formula (1)
represents an ion bond, and in case where R.sup.4 represents a
lithium ion, a sodium ion or a potassium ion, a bond of the
nitrogen atom and R.sup.4 in the general formula (1) represents an
ion bond].
2. The nonaqueous electrolyte solution according to claim 1,
wherein R.sup.1 and R.sup.2 in the general formula (1) each
independently represents POF.sub.2 or SO.sub.2F.
3. The nonaqueous electrolyte solution according to claim 1,
wherein both R.sup.1 and R.sup.2 in the general formula (1)
represent SO.sub.2F.
4. The nonaqueous electrolyte solution according to claim 1,
wherein R.sup.3 and R.sup.4 in the general formula (1) each
independently represents a hydrogen atom, a lithium ion, a sodium
ion, or a C1-4 linear or C3-4 branched alkyl group.
5. The nonaqueous electrolyte solution according to claim 1,
wherein the compound represented by the general formula (1) is a
compound represented by the following formula (1a).
##STR00009##
6. The nonaqueous electrolyte solution according to claim 1,
wherein the nonaqueous organic solvent contains at least one
selected from the group consisting of a cyclic carbonate and a
chain carbonate.
7. The nonaqueous electrolyte solution according to claim 6,
wherein the cyclic carbonate is at least one selected from the
group consisting of ethylene carbonate, propylene carbonate and
fluoroethylene carbonate, and the chain carbonate is at least one
selected from the group consisting of ethylmethyl carbonate,
dimethyl carbonate, diethyl carbonate and methylpropyl
carbonate.
8. The nonaqueous electrolyte solution according to claim 1,
wherein an amount of the compound represented by the general
formula (1) with respect to the total amount of the compound
represented by the general formula (1), the solute, and the
nonaqueous organic solvent is 0.01 mass % to 10.0 mass %.
9. The nonaqueous electrolyte solution according to claim 1,
further containing at least one selected from vinylene carbonate,
lithium bis(oxalato)borate, lithium difluoro(oxalato)borate,
lithium difluorobis(oxalato)phosphate, lithium
tetrafluoro(oxalato)phosphate, lithium bis(fluorosulfonyl)imide,
lithium (difluorophosphoryl)(fluorosulfonyl)imide,
1,3-propenesultone and 1,3-propanesultone in an amount of 0.01 mass
% to 5.0 mass % with respect to the total amount of the nonaqueous
electrolyte solution.
10. A nonaqueous electrolyte battery, comprising a positive
electrode, a negative electrode, and the nonaqueous electrolyte
solution according to claim 1.
11. A compound represented by the following formula (1a).
##STR00010##
Description
TECHNICAL FIELD
[0001] The present invention relates to a nonaqueous electrolyte
solution, a nonaqueous electrolyte battery, and a compound.
BACKGROUND TECHNOLOGY
[0002] For batteries as electrochemical devices, in recent years,
storage systems to be applied to small equipment that needs high
energy density, such as information-technology-related equipment or
communication equipment, specifically, personal computers, video
cameras, digital still cameras, cell phones and smartphones and
storage systems to be applied to large equipment that needs high
power, such as auxiliary power and energy storage for electric
vehicles, hybrid electric vehicles and fuel cell electric vehicles
have attracted attention. Currently, a nonaqueous electrolyte
battery, including a lithium ion battery with high energy density
and voltage and large capacity, has been actively studied and
developed as a candidate thereof.
[0003] As a nonaqueous electrolyte solution used for such
nonaqueous electrolyte batteries, a nonaqueous electrolyte solution
obtained by dissolving a fluorine-containing electrolyte such as
lithium hexafluorophosphate (hereinafter LiPF.sub.6), lithium
bis(fluorosulfonylimide) (hereinafter LFSI) or lithium
tetrafluoroborate (hereinafter LiBF.sub.4) as a solute in a solvent
such as a cyclic carbonate, a chain carbonate or an ester is
suitable to obtain a battery with high voltage and large capacity,
and thus frequently used. However, nonaqueous electrolyte batteries
using such a nonaqueous electrolyte solution do not necessarily
have satisfactory battery characteristics such as cycle
characteristics and output characteristics.
[0004] In the case of lithium ion secondary batteries, for example,
when the lithium cation is inserted into a negative electrode at
the initial charge, the negative electrode and the lithium cation,
or the negative electrode and the solvent of an electrolyte
solution react to form a film having lithium oxide, lithium
carbonate and/or lithium alkyl carbonate as a main component on the
negative electrode surface. This film on the electrode surface is
called Solid Electrolyte Interface (SEI), and the properties
thereof have large influences on battery performance, for example,
suppressing further reduction decomposition of a solvent and
suppressing the deterioration of battery performance. Similarly, a
film is also formed on the positive electrode surface from
decomposed products, and it is known that this film also suppresses
the oxidative decomposition of a solvent and plays an important
role in, for example, suppressing the generation of gas inside the
battery.
[0005] In order to improve durability such as cycle characteristics
and high temperature storage characteristics and battery
characteristics including input and output characteristics, it is
important to form a stable SEI having a high ion conductivity and a
low electron conductivity, and an attempt to positively form a good
SEI has been widely made by way of adding a small amount of a
compound called an additive to an electrolyte solution (usually
0.001 mass % or more and 10 mass % or less).
[0006] The optimization of various battery components including
active materials of a positive electrode and a negative electrode
has been investigated as a means for improving durability such as
cycle characteristics and high temperature storage characteristics
of nonaqueous electrolyte batteries until now. Technologies related
to nonaqueous electrolyte solutions are no exception, and it has
been proposed that deterioration due to the decomposition of a
nonaqueous electrolyte solution on the active positive electrode
and negative electrode surfaces is suppressed by various
additives.
[0007] Patent Literature 1 proposes that battery characteristics
such as high temperature storage characteristics are improved by
adding vinylene carbonate to a nonaqueous electrolyte solution.
This method prevents the decomposition of a nonaqueous electrolyte
solution on electrode surfaces by way of coating electrodes with
polymer films formed due to polymerization of vinylene carbonate;
however, lithium ion is also difficult to pass through this film
and thus there is a problem of an increase in internal
resistance.
[0008] In order to solve this problem, the addition of lithium
difluorophosphate disclosed in Patent Literature 2 is effective,
and it is known that batteries, in which an increase in internal
resistance is suppressed while simultaneously high storage
characteristics at high temperatures are maintained, are obtained
by using vinylene carbonate and lithium difluorophosphate in
combination.
[0009] Patent Literature 3 discloses a method for improving input
and output characteristics and impedance characteristics by causing
a nonaqueous electrolyte solution to contain a fluorosulfonic acid
salt as a single additive, not a combination of a plurality of
additives.
PRIOR ART REFERENCES
Patent Literature
[0010] Patent Literature 1: JP-B-3438636 [0011] Patent Literature
2: JP-B-3439085 [0012] Patent Literature 3: JP-A-2013-152956
SUMMARY OF INVENTION
Subject to be Attained by the Invention
[0013] As a result of the examination by the present inventors, the
present inventors have found that the effect of suppressing an
increase in internal resistance is low even when lithium
difluorophosphate is added to a nonaqueous electrolyte solution
including vinylene carbonate, and that the effect of improving
initial input and output characteristics is low even when a
nonaqueous electrolyte solution comprising lithium fluorosulfonate
described in Patent Literature 3 was used. In this way, there has
been room for examination of resistance characteristics,
particularly initial resistance characteristics.
[0014] The present invention has been made in view of the above
circumstances, and the subject to be attained by the present
invention is to provide a nonaqueous electrolyte solution which can
provide a low initial resistance value when it is used in a
nonaqueous electrolyte battery. Another subject to be attained by
the present invention is to provide a compound which can be
suitably used in the above nonaqueous electrolyte solution.
Means for Attaining the Above Subject
[0015] As a result of intense and diligent studies in view of such
subjects, the present inventors have found that a nonaqueous
electrolyte battery providing a low initial resistance value when
it is used in a nonaqueous electrolyte battery is obtained by
causing a nonaqueous electrolyte solution to comprise a compound
represented by the general formula (1) which will be explained in
detail below, a solute, and a nonaqueous organic solvent, thereby
completing the present invention.
[0016] That is, the present inventors found that the above subjects
can be attained by the following constitutions.
[1] A nonaqueous electrolyte solution, comprising a compound
represented by the following general formula (1), a solute, and a
nonaqueous organic solvent:
##STR00001##
[in the general formula (1),
[0017] R.sup.1 and R.sup.2 each independently represents
PO(R.sub.f).sub.2 or SO.sub.2R.sub.f,
[0018] R.sub.fs each independently represents a fluorine atom or a
C1-4 linear or C3-4 branched perfluoroalkyl group,
[0019] R.sup.3 and R.sup.4 each independently represents a hydrogen
atom, a lithium ion, a sodium ion, a potassium ion, or a C1-12
linear or C3-12 branched alkyl group, wherein an oxygen atom may be
included between the carbon atoms of the carbon atom-carbon atom
bond in the alkyl group, or
[0020] R.sup.3 and R.sup.4 form a ring structure together with the
nitrogen atoms to which they are bound, wherein R.sup.3 and
R.sup.4, together with each other, form an alkylene group; an
oxygen atom may be included between the carbon atoms of the carbon
atom-carbon atom bond in the alkylene group; a side chain thereof
may have an alkyl group; and an arbitrary hydrogen atom in the
alkyl group and alkylene group may be substituted by a fluorine
atom,
[0021] provided that in case where R.sup.3 represents a lithium
ion, a sodium ion or a potassium ion, a bond of the nitrogen atom
and R.sup.3 in the general formula (1) represents an ion bond, and
in case where R.sup.4 represents a lithium ion, a sodium ion or a
potassium ion, a bond of the nitrogen atom and R.sup.4 in the
general formula (1) represents an ion bond].
[2] The nonaqueous electrolyte solution according to [1], wherein
R.sup.1 and R.sup.2 in the general formula (1) each independently
represents POF.sub.2 or SO.sub.2F. [3] The nonaqueous electrolyte
solution according to [1] or [2], wherein both R.sup.1 and R.sup.2
in the general formula (1) represent SO.sub.2F. [4] The nonaqueous
electrolyte solution according to any one of [1] to [3], wherein
R.sup.3 and R.sup.4 in the general formula (1) each independently
represents a hydrogen atom, a lithium ion, a sodium ion, or a C1-4
linear or C3-4 branched alkyl group. [5] The nonaqueous electrolyte
solution according to any one of [1] to [4], wherein the compound
represented by the general formula (1) is a compound represented by
the following formula (1a).
##STR00002##
[6] The nonaqueous electrolyte solution according to any one of [1]
to [5], wherein the nonaqueous organic solvent contains at least
one selected from the group consisting of a cyclic carbonate and a
chain carbonate. [7] The nonaqueous electrolyte solution according
to [6], wherein the cyclic carbonate is at least one selected from
the group consisting of ethylene carbonate, propylene carbonate and
fluoroethylene carbonate, and the chain carbonate is at least one
selected from the group consisting of ethylmethyl carbonate,
dimethyl carbonate, diethyl carbonate and methylpropyl carbonate.
[8] The nonaqueous electrolyte solution according to any one of [1]
to [7], wherein an amount of the compound represented by the
general formula (1) with respect to the total amount of the
compound represented by the general formula (1), the solute and the
nonaqueous organic solvent is 0.01 mass % to 10.0 mass %. [9] The
nonaqueous electrolyte solution according to any one of [1] to [8],
further containing at least one selected from vinylene carbonate,
lithium bis(oxalato)borate, lithium difluoro(oxalato)borate,
lithium difluorobis(oxalato)phosphate, lithium
tetrafluoro(oxalato)phosphate, lithium bis(fluorosulfonyl)imide,
lithium (difluorophosphoryl)(fluorosulfonyl)imide,
1,3-propenesultone and 1,3-propanesultone in an amount of 0.01 mass
% to 5.0 mass % with respect to the total amount of the nonaqueous
electrolyte solution. [10] A nonaqueous electrolyte battery,
comprising a positive electrode, a negative electrode, and the
nonaqueous electrolyte solution according to any one of [1] to [9].
[11] A compound represented by the following formula (1a).
##STR00003##
Effect by the Invention
[0022] According to the present invention, it is possible to
provide a nonaqueous electrolyte solution with a low initial
resistance value when it is used in a nonaqueous electrolyte
battery. It is also possible to provide a compound which can be
suitably used for the above nonaqueous electrolyte solution.
DESCRIPTION OF EMBODIMENTS
[0023] Constitutions and combinations thereof in the following
embodiments are merely described as examples, and various
modifications may be made without departing from the gist of the
present invention. In addition, the present invention is not
limited by the embodiments, and limited only by the claims.
[0024] In the present specification, the term "-" or "--- to ---"
is used to mean including the values described before and after it
as the lower limit and upper limit.
[0025] In the present specification, the term "initial resistance
value" represents a resistance value of a nonaqueous electrolyte
battery immediately after charge and discharge operations which are
initially performed to stabilize the battery. Specifically, it
indicates a resistance value by impedance determination immediately
after 3 cycles of charge and discharge operations to stabilize the
battery.
[1. Nonaqueous Electrolyte Solution]
[0026] The nonaqueous electrolyte solution of the present invention
is a nonaqueous electrolyte solution comprising a compound
represented by the above general formula (1), a solute, and a
nonaqueous organic solvent.
<(I) Compound Represented by the General Formula (1)>
[0027] The nonaqueous electrolyte solution of the present invention
includes a compound represented by the general formula (1).
[0028] When a nonaqueous electrolyte solution including a compound
represented by the general formula (1) is used for a nonaqueous
electrolyte battery (e.g. a lithium ion secondary battery), the
compound represented by the general formula (1) is decomposed on
the positive electrode and negative electrode, and a film with a
good ion conductivity is formed on the surfaces of the positive
electrode and negative electrode. It is thought that this film
suppresses the direct contact of the nonaqueous organic solvent or
solute and electrode active materials to reduce a Li ion
dissociation energy of the solute. Consequently, the present
inventors presume that the effect of reducing the initial
resistance of a nonaqueous electrolyte battery is displayed.
[0029] The compound represented by the general formula (1) will now
be described.
[0030] In the general formula (1), R.sup.1 and R.sup.2 each
independently represents PO(R.sub.f).sub.2 or SO.sub.2R.sub.f.
[0031] R.sub.f represents a fluorine atom, or a C1-4 linear or C3-4
branched perfluoroalkyl group.
[0032] In case where R.sub.f represents a C1-4 linear or C3-4
branched perfluoroalkyl group, specific examples thereof include
e.g. a trifluoromethyl group, a pentafluoroethyl group, a
heptafluoropropyl group, a heptafluoroisopropyl group, a
nonafluoro-n-butyl group and the like. Among them, a
trifluoromethyl group is preferred.
[0033] R.sub.f preferably represents a fluorine atom.
[0034] Two R.sub.fs in PO(R.sub.f).sub.2 may be the same or
different.
[0035] It is preferred that R.sup.1 and R.sub.2 each independently
represents POF.sub.2 or SO.sub.2F, and it is preferred that both
R.sup.1 and R.sup.2 represent SO.sub.2F.
[0036] In the general formula (1), R.sup.3 and R.sup.4 each
independently represents a hydrogen atom, a lithium ion, a sodium
ion, a potassium ion, or a C1-12 linear or C3-12 branched alkyl
group.
[0037] In case where R.sup.3 and R.sup.4 represent C1-12 linear or
C3-12 branched alkyl groups, specific examples thereof include e.g.
a methyl group, an ethyl group, an n-propyl group, an isopropyl
group, an n-butyl group, a sec-butyl group, an isobutyl group, a
tert-butyl group, an n-pentyl group and the like.
[0038] An oxygen atom may be included between the carbon atoms of
the carbon atom-carbon atom bond in the above alkyl group. In case
where an oxygen atom is included between the carbon atoms in the
carbon atom-carbon atom bond in the above alkyl group, specific
examples thereof include e.g. a 2-methoxyethyl group, a
2-ethoxyethyl group and the like.
[0039] An arbitrary hydrogen atom in the above alkyl group may be
substituted by a fluorine atom. In case where an arbitrary hydrogen
atom is substituted by a fluorine atom, examples of the alkyl group
include a trifluoromethyl group, a difluoromethyl group, a
fluoromethyl group, a 2,2,2-trifluoroethyl group, a
2,2-difluoroethyl group, a 2-fluoroethyl group, a 3-fluoropropyl
group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl
group, a 2,2,3,3-tetrafluoropropyl group, a hexafluoroisopropyl
group and the like.
[0040] It is preferred that the above alkyl group be an alkyl group
having 6 or less carbon atoms because resistance when a film is
formed on electrodes can be lowered. The above alkyl group is more
preferably an alkyl group having 4 or less carbon atoms, and
particularly preferably a methyl group, an ethyl group, an n-propyl
group, an isopropyl group, an n-butyl group, or a tert-butyl
group.
[0041] R.sup.3 and R.sup.4 each independently represents preferably
a hydrogen atom, a lithium ion, a sodium ion, or a C1-4 alkyl
group, and more preferably a hydrogen atom, a lithium ion, a sodium
ion, or a methyl group, and it is further preferred that both
R.sup.3 and R.sup.4 represent lithium ions.
[0042] In addition, R.sup.3 and R.sup.4 may form a ring structure
together with the nitrogen atoms to which they are bound. In this
case, R.sup.3 and R.sup.4, together with each other, form a C2-4
alkylene group, an oxygen atom may be included between the carbon
atoms of the carbon atom-carbon atom bond in the alkylene group,
and a side chain thereof may have an alkyl group. In addition, an
arbitrary hydrogen atom in the alkyl group and alkylene group may
be substituted by a fluorine atom.
[0043] Examples of the alkylene group include an ethylene group, a
propylene group and the like, and it is particularly preferably an
ethylene group.
[0044] Specifically, the compound represented by the general
formula (1) is preferably at least one selected from the group
consisting of compounds represented by formulae (1a) to (1y), which
will be specifically shown below.
[0045] It is more preferably at least one selected from the group
consisting of a compound represented by formula (1a) (referred to
as compound (1a)), a compound represented by formula (1b) (referred
to as compound (1b)), a compound represented by formula (1c)
(referred to as compound (1c)), a compound represented by formula
(1e) (referred to as compound (1e)), a compound represented by
formula (1p) (referred to as compound (1p)), and a compound
represented by formula (1w) (referred to as compound (1w)), further
preferably at least one selected from the group consisting of
compound (1a), compound (1e) and compound (1w), and particularly
preferably compound (1a).
##STR00004## ##STR00005## ##STR00006##
[0046] It should be noted that the present invention also relates
to the above compound (1a).
[0047] In the nonaqueous electrolyte solution of the present
invention, the above compound represented by the general formula
(1) is preferably used as an additive.
[0048] In the nonaqueous electrolyte solution of the present
invention, the total amount of the compound represented by the
general formula (1) (hereinafter referred to as "concentration of
compound represented by the general formula (1)") with respect to
the total amount of the above compound represented by the general
formula (1), a solute and a nonaqueous organic solvent (100 mass %)
is, as the lower limit, preferably 0.01 mass % or more, more
preferably 0.05 mass % or more, and further preferably 0.1 mass %
or more. The upper limit of the concentration of the compound
represented by the general formula (1) is preferably 10.0 mass % or
less, more preferably 5.0 mass % or less, and further preferably
2.0 mass % or less.
[0049] When the concentration of the compound represented by the
general formula (1) is 0.01 mass % or more, the effect of
suppressing an increase in the initial resistance of a nonaqueous
electrolyte battery using the nonaqueous electrolyte solution is
easily obtained. Meanwhile, when the concentration of the compound
represented by the general formula (1) is 10.0 mass % or less, an
increase in the viscosity of the nonaqueous electrolyte solution
can be suppressed, and the effect of improving high temperature
cycle characteristics of a nonaqueous electrolyte battery using the
nonaqueous electrolyte solution is easily obtained.
[0050] As one embodiment of the nonaqueous electrolyte solution of
the present invention, so long as the concentration of the compound
represented by the general formula (1) is not above 10.0 mass %,
the compounds may be used singly or two or more of the compounds
may be used in any combination at any ratio based on
applications.
[0051] The method for synthesizing a compound represented by the
above general formula (1) is not particularly limited, and the
compound can be synthesized, for example, by the reaction of
fluorosulfonyl isocyanate and water or the reaction of phosgene and
methylsulfamoyl fluoride as described in Chemische Berichte (1968),
101(1), 162-73, and Journal of Chemical Research, Synopses (1977),
(10), 237.
[0052] Furthermore, the compound represented by the above general
formula (1) wherein each of R.sup.3 and R.sup.4 represent a lithium
ion, a sodium ion or a potassium ion can be synthesized by reaction
with an inorganic base such as an alkali metal hydride ion.
<(II) Solute>
[0053] The nonaqueous electrolyte solution of the present invention
comprises a solute.
[0054] The solute is not particularly limited and is preferably an
ionic salt and more preferably an ionic salt including a fluorine
atom.
[0055] For example, the solute is preferably an ionic salt
comprising a pair of at least one cation selected from the group
consisting of an alkali metal ion including a lithium ion and a
sodium ion, an alkaline earth metal ion and quaternary ammonium,
with at least one anion selected from the group consisting of a
hexafluorophosphate anion a tetrafluoroborate anion, a perchlorate
anion, a hexafluoroarsenate anion, a hexafluoroantimonate anion, a
trifluoromethanesulfonate anion, a
bis(trifluoromethanesulfonyl)imide anion, a
bis(pentafluoroethanesulfonyl)imide anion, a
(trifluoromethanesulfonyl)(pentafluoroethanesulfonyl)imide anion, a
bis(fluorosulfonyl)imide anion, a
(trifluoromethanesulfonyl)(fluorosulfonyl)imide anion, a
(pentafluoroethanesulfonyl)(fluorosulfonyl)imide anion, a
tris(trifluoromethanesulfonyl)methide anion, a
bis(difluorophosphoryl)imide anion, a
(difluorophosphoryl)(trifluoromethanesulfonyl)imide anion, a
(difluorophosphoryl)(fluorosulfonyl)imide anion, and a
difluorophosphate anion.
[0056] These solutes may be used singly or two or more of the
solutes may be used in any combination at any ratio based on
applications.
[0057] Among them, it is preferred that the cation be at least one
selected from the group consisting of lithium, sodium, magnesium
and quaternary ammonium, and the anion be at least one selected
from the group consisting of a hexafluorophosphate anion, a
tetrafluoroborate anion, a bis(trifluoromethanesulfonyl)imide
anion, a bis(fluorosulfonyl)imide anion, a
bis(difluorophosphoryl)imide anion, a
(difluorophosphoryl)(fluorosulfonyl)imide anion, and a
difluorophosphoric acid anion in respect of energy density, output
characteristics, battery life and the like as a nonaqueous
electrolyte battery.
[0058] The total amount of a solute in the nonaqueous electrolyte
solution of the present invention (hereinafter, referred to as
"solute concentration") is not particularly restricted, and the
lower limit is preferably 0.5 mol/L or more, more preferably 0.7
mol/L or more, and further preferably 0.9 mol/L or more. The upper
limit of the solute concentration is preferably 5.0 mol/L or less,
more preferably 4.0 mol/L or less, and further preferably 2.0 mol/L
or less. When the solute concentration is 0.5 mol/L or more,
reductions in cycle characteristics and output characteristics of a
nonaqueous electrolyte battery due to ion conductivity reduction
can be suppressed, and when the solute concentration is 5.0 mol/L
or less, an ion conductivity reduction due to an increase in the
viscosity of the nonaqueous electrolyte solution and reductions in
cycle characteristics and output characteristics of a nonaqueous
electrolyte battery can be suppressed.
<(III) Nonaqueous Organic Solvent>
[0059] The type of nonaqueous organic solvent used for the
nonaqueous electrolyte solution of the present invention is not
particularly limited, and any nonaqueous organic solvent can be
used.
[0060] Specifically, it is preferably at least one selected from
the group consisting of ethylmethyl carbonate (hereinafter referred
to as "EMC"), dimethyl carbonate (hereinafter referred to as
"DMC"), diethyl carbonate (hereinafter referred to as "DEC"),
methylpropyl carbonate, ethylpropyl carbonate, methylbutyl
carbonate, 2,2,2-trifluoroethylmethyl carbonate,
2,2,2-trifluoroethylethyl carbonate, 2,2,2-trifluoroethylpropyl
carbonate, bis(2,2,2-trifluoroethyl) carbonate,
1,1,1,3,3,3-hexafluoro-1-propylmethyl carbonate,
1,1,1,3,3,3-hexafluoro-1-propylethyl carbonate,
1,1,1,3,3,3-hexafluoro-1-propylpropyl carbonate,
bis(1,1,1,3,3,3-hexafluoro-1-propyl) carbonate, ethylene carbonate
(hereinafter referred to as "EC"), propylene carbonate (hereinafter
referred to as "PC"), butylene carbonate, fluoroethylene carbonate
(hereinafter referred to as "FEC"), difluoroethylene carbonate,
methyl acetate, ethyl acetate, methyl propionate, ethyl propionate,
methyl 2-f luoropropionate, ethyl 2-fluoropropionate, diethyl
ether, dibutyl ether, diisopropyl ether, 1,2-dimethoxyethane,
tetrahydrofuran, 2-methyltetrahydrofuran, furan, tetrahydropyran,
1,3-dioxane, 1,4-dioxane, N,N-dimethylformamide, acetonitrile,
propionitrile, dimethyl sulfoxide, sulfolane, y-butyrolactone, and
.gamma.-valerolactone.
[0061] In addition, an ionic liquid which takes a salt structure
may be used as a nonaqueous organic solvent in the present
invention.
[0062] In addition, it is preferred that the above nonaqueous
organic solvent be at least one selected from the group consisting
of a cyclic carbonate and a chain carbonate in that cycle
characteristics at high temperatures are excellent. In addition, it
is preferred that the above nonaqueous organic solvent be at least
one selected from the group consisting of esters in that input and
output characteristics at low temperatures are excellent.
[0063] Specific examples of the above cyclic carbonate include EC,
PC, butylene carbonate, and FEC and the like, and among them, at
least one selected from the group consisting of EC, PC and FEC is
preferred.
[0064] Specific examples of the above chain carbonate include EMC,
DMC, DEC, methylpropyl carbonate, ethylpropyl carbonate,
2,2,2-trifluoroethylmethyl carbonate, 2,2,2-trifluoroethylethyl
carbonate, 1,1,1,3,3,3-hexafluoro-1-propylmethyl carbonate, and
1,1,1,3,3,3-hexafluoro-1-propylethyl carbonate, and the like, and
among them, at least one selected from the group consisting of EMC,
DMC, DEC, and methylpropyl carbonate is preferred.
[0065] In addition, specific examples of the above esters include
methyl acetate, ethyl acetate, methyl propionate, ethyl propionate,
methyl 2-f luoropropionate, and ethyl 2-fluoropropionate, and the
like.
<Other Additives>
[0066] Additional components commonly used may be further added at
any ratio to the nonaqueous electrolyte solution of the present
invention without losing the gist of the present invention.
[0067] Specific examples of the other additives include compounds
having the effect of preventing overcharge, the effect of forming a
negative electrode film, and the effect of protecting a positive
electrode such as cyclohexylbenzene, cyclohexylfluorobenzene,
fluorobenzene, biphenyl, difluoroanisole, tert-butylbenzene,
tert-amylbenzene, 2-fluorotoluene, 2-fluorobiphenyl, vinylene
carbonate, dimethylvinylene carbonate, vinyl ethylene carbonate,
fluoroethylene carbonate, trans-difluoroethylene carbonate, methyl
propargyl carbonate, ethyl propargyl carbonate, dipropargyl
carbonate, maleic anhydride, succinic anhydride, propanesultone,
1,3-propanesultone, 1,3-propenesultone, butanesultone, methylene
methanedisulfonate, dimethylene methanedisulfonate, trimethylene
methanedisulfonate, methyl methanesulfonate,
1,6-diisocyanatohexane, tris(trimethylsilyl)borate, succinonitrile,
(ethoxy) pentafluorocyclotriphosphazene, lithium
difluorobis(oxalato)phosphate, sodium
difluorobis(oxalato)phosphate, potassium
difluorobis(oxalato)phosphate, lithium difluoro(oxalato)borate,
sodium difluoro(oxalato)borate, potassium difluoro(oxalato)borate,
lithium bis(oxalato)borate, sodium bis(oxalato)borate, potassium
bis(oxalato)borate, lithium tetrafluoro(oxalato)phosphate, sodium
tetrafluoro(oxalato)phosphate, potassium
tetrafluoro(oxalato)phosphate, lithium tris(oxalato)phosphate,
lithium ethylfluorophosphate, lithium fluorophosphate,
ethenesulfonyl fluoride, lithium fluorosulfonate,
trifluoromethanesulfonyl fluoride, methanesulfonyl fluoride, and
phenyl difluorophosphate.
[0068] The nonaqueous electrolyte solution of the present invention
may include as the other additives, a compound represented by the
following general formula (2):
##STR00007##
[in the general formula (2), R.sup.5-R.sup.7 each independently
represents a fluorine atom, or an organic group selected from a
C1-10 linear or branched alkyl group, a C1-10 linear or branched
alkoxy group, a C2-10 alkenyl group, a C2-10 alkenyloxy group, a
C2-10 alkynyl group, a C2-10 alkynyloxy group, a C3-10 cycloalkyl
group, a C3-10 cycloalkoxy group, a C3-10 cycloalkenyl group, a
C3-10 cycloalkenyloxy group, a C6-10 aryl group, and a C6-10
aryloxy group, wherein a fluorine atom, an oxygen atom or an
unsaturated bond may exist in the organic group, provided that at
least one of R.sup.5 to R.sup.7 represents a fluorine atom.
[0069] M.sup.m+ represents an alkali metal cation, an alkaline
earth metal cation, or an onium cation, and m represents an integer
having the same number as the valence of the corresponding
cation].
[0070] When the compound represented by the general formula (2) (a
salt having an imide anion) has at least one P--F bond or S--F
bond, excellent low temperature characteristics are obtained. The
larger number of P--F bonds or S--F bonds in the above salt having
an imide anion is more preferred in that low temperature
characteristics can be further improved, and in the above salt
having an imide anion represented by the general formula (2), a
compound wherein all R.sup.5 to R.sup.7 are fluorine atoms is
further preferred.
[0071] It is also preferred that in the above salt having an imide
anion represented by the general formula (2),
[0072] at least one of R.sup.5 to R.sup.7 be a fluorine atom,
[0073] at least one of R.sup.5 to R.sup.7 be a compound selected
from hydrocarbon groups having 6 or less carbon atoms which may
have a fluorine atom.
[0074] It is also preferred that in the above salt having an imide
anion represented by the general formula (2),
[0075] at least one of R.sup.5 to R.sup.7 be a fluorine atom,
[0076] at least one of R.sup.5 to R.sup.7 be a compound selected
from a methyl group, a methoxy group, an ethyl group, an ethoxy
group, a propyl group, a propoxyl group, a vinyl group, an allyl
group, an allyloxy group, an ethynyl group, a 2-propynyl group, a
2-propynyloxy group, a phenyl group, a phenyloxy group, a
2,2-difluoroethyl group, a 2,2-difluoroethyloxy group, a
2,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyloxy group, a
2,2,3,3-tetrafluoropropyl group, a 2,2,3,3-tetrafluoropropyloxy
group, a 1,1,1,3,3,3-hexafluoroisopropyl group, and a
1,1,1,3,3,3-hexafluoroisopropyloxy group.
[0077] The counter cation M.sup.m+ of the above salt having an
imide anion represented by the general formula (2) is preferably
selected from the group consisting of a lithium ion, a sodium ion,
a potassium ion and a tetraalkylammonium ion.
[0078] In addition, examples of the alkyl group and alkoxyl group
represented by R.sup.5 to R.sup.7 in the above general formula (2)
include C1-10 alkyl groups and fluorine-containing alkyl groups
such as a methyl group, an ethyl group, a propyl group, an
isopropyl group, a butyl group, a secondary butyl group, a tertiary
butyl group, a pentyl group, a 2,2-difluoroethyl group, a
2,2,2-trifluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, and
a 1,1,1,3,3,3-hexafluoroisopropyl group, and alkoxy groups derived
from these groups.
[0079] Examples of the alkenyl group and alkenyloxy group include
C2-10 alkenyl groups and fluorine-containing alkenyl groups such as
a vinyl group, an allyl group, a 1-propenyl group, an isopropenyl
group, a 2-butenyl group, and a 1,3-butadienyl group, and
alkenyloxy groups derived from these groups.
[0080] Examples of the alkynyl group and alkynyloxy group include
C2-10 alkynyl groups and fluorine-containing alkynyl groups such as
an ethynyl group, a 2-propynyl group and a 1,1-dimethyl-2-propynyl
group, and alkynyloxy groups derived from these groups.
[0081] Examples of the cycloalkyl group and cycloalkoxy group
include C3-10 cycloalkyl groups and fluorine-containing cycloalkyl
groups such as a cyclopentyl group and a cyclohexyl group, and
cycloalkoxy groups derived from these groups.
[0082] Examples of the cycloalkenyl group and cycloalkenyloxy group
include C3-10 cycloalkenyl groups and fluorine-containing
cycloalkenyl groups such as a cyclopentenyl group and a
cyclohexenyl group, and cycloalkenyloxy groups derived from these
groups.
[0083] Examples of the aryl group and aryloxy group include C6-10
aryl groups and fluorine-containing aryl groups such as a phenyl
group, a tolyl group and a xylyl group, and aryloxy groups derived
from these groups.
[0084] Specific examples of the above salt having an imide anion
represented by the general formula (2) and the method for
synthesizing the salt can include those described in
WO2017/111143.
[0085] The amount of such other additives in the nonaqueous
electrolyte solution is preferably 0.01 mass % or more and 8.0 mass
% or less with respect to the total amount of the nonaqueous
electrolyte solution.
[0086] In addition, the ionic salts mentioned as a solute can
display the effect of forming a negative electrode film and the
effect of protecting a positive electrode as "other additives" when
the amount included in the nonaqueous electrolyte solution is
smaller than 0.5 mol/L as the lower limit of a suitable
concentration of the solute. In this case, the amount included in
the nonaqueous electrolyte solution is preferably 0.01 mass % to
5.0 mass %.
[0087] Examples of the ionic salt in this case include lithium
trifluoromethanesulfonate, sodium trifluoromethanesulfonate,
potassium trifluoromethanesulfonate, magnesium
trifluoromethanesulfonate, lithium
bis(trifluoromethanesulfonyl)imide, sodium
bis(trifluoromethanesulfonyl)imide, potassium
bis(trifluoromethanesulfonyl)imide, magnesium
bis(trifluoromethanesulfonyl)imide, lithium
bis(fluorosulfonyl)imide, sodium bis(fluorosulfonyl)imide,
potassium bis(fluorosulfonyl)imide, magnesium
bis(fluorosulfonyl)imide, lithium
(trifluoromethanesulfonyl)(fluorosulfonyl)imide, sodium
(trifluoromethanesulfonyl)(fluorosulfonyl)imide, potassium
(trifluoromethanesulfonyl)(fluorosulfonyl)imide, magnesium
(trifluoromethanesulfonyl)(fluorosulfonyl)imide, lithium
bis(difluorophosphoryl)imide, sodium bis(difluorophosphoryl)imide,
potassium bis(difluorophosphoryl)imide, magnesium
bis(difluorophosphoryl)imide, lithium
(difluorophosphoryl)(fluorosulfonyl)imide, sodium
(difluorophosphoryl)(fluorosulfonyl)imide, potassium
(difluorophosphoryl)(fluorosulfonyl)imide, magnesium
(difluorophosphoryl)(fluorosulfonyl)imide, lithium
(difluorophosphoryl)(trifluoromethanesulfonyl)imide, sodium
(difluorophosphoryl)(trifluoromethanesulfonyl)imide, potassium
(difluorophosphoryl)(trifluoromethanesulfonyl)imide, magnesium
(difluorophosphoryl)(trifluoromethanesulfonyl)imide, lithium
difluorophosphate, sodium difluorophosphate, and the like.
[0088] In addition, alkali metal salts other than the above solutes
(lithium salt, sodium salt, potassium salt and magnesium salt) may
be used as additives.
[0089] Specific examples thereof include carboxylic acid salts such
as lithium acrylate, sodium acrylate, lithium methacrylate, and
sodium methacrylate, sulfuric acid ester salts such as lithium
methyl sulfate, sodium methyl sulfate, lithium ethyl sulfate,
sodium ethyl sulfate, and the like.
[0090] The nonaqueous electrolyte solution of the present invention
preferably contains, among the above other additives, at least one
selected from vinylene carbonate, lithium bis(oxalato)borate,
lithium difluoro(oxalato)borate, lithium
difluorobis(oxalato)phosphate, lithium tetrafluoro
(oxalato)phosphate, lithium bis(fluorosulfonyl)imide, lithium
(difluorophosphoryl)(fluorosulfonyl)imide, 1,3-propenesultone and
1,3-propanesultone in an amount of 0.01 mass % to 5.0 mass % with
respect to the total amount of the nonaqueous electrolyte
solution.
[0091] The nonaqueous electrolyte solution further preferably
contains at least one selected from lithium
difluoro(oxalato)borate, lithium
(difluorophosphoryl)(fluorosulfonyl)imide and lithium
difluorobis(oxalato)phosphate from the viewpoint of suppressing an
increase in an initial resistance value.
[0092] In addition, the nonaqueous electrolyte solution of the
present invention may include a polymer, and a pseudo solid of the
nonaqueous electrolyte solution obtained using a gelling agent or a
cross-linking polymer can be used as in the case of a nonaqueous
electrolyte battery called polymer battery. In the polymer solid
electrolytes, those containing a nonaqueous organic solvent as a
plasticizing agent are also included.
[0093] The above polymer is not particularly limited so long as it
is an aprotic polymer which can dissolve the above compound
represented by the general formula (1), the above solute and the
above other additives. Examples thereof include a polymer having
polyethylene oxide as a main chain or a side chain, a homopolymer
or copolymer of polyvinylidene fluoride, a methacrylic acid ester
polymer, a polyacrylonitrile, and the like. When a plasticizing
agent is added to these polymers, an aprotic nonaqueous organic
solvent is preferred among the above nonaqueous organic
solvents.
[2. Nonaqueous Electrolyte Battery]
[0094] The nonaqueous electrolyte battery of the present invention
comprises at least the above nonaqueous electrolyte solution of the
present invention, a negative electrode, and a positive electrode,
and moreover preferably comprises a separator, packaging, and the
like.
[0095] The negative electrode is not particularly limited, and
materials into and from which an alkali metal ion such as a lithium
ion or a sodium ion or an alkali earth metal ion can be reversibly
inserted and extracted are preferably used.
[0096] The positive electrode is not particularly limited, and
materials into and from which an alkali metal ion such as a lithium
ion or a sodium ion or an alkali earth metal ion can be reversibly
inserted and extracted are preferably used.
[0097] When the cation is lithium, for example, lithium metal, an
alloy or intermetallic compound of lithium with another metal; and
various carbon materials, metal oxides, metal nitrides, activated
carbon, conductive polymers and the like, which can occlude and
release lithium, are used as a negative electrode material.
Examples of the above carbon materials include easily graphitizable
carbon, difficultly graphitizable carbon with a (002) plane spacing
of 0.37 nm or more (also called hard carbon), graphite with a (002)
plane spacing of 0.37 nm or less, and the like, and as the latter,
artificial graphite, natural graphite and the like are used.
[0098] When the cation is lithium, for example, lithium-containing
transition metal composite oxide such as LiCoO.sub.2, LiNiO.sub.2,
LiMnO.sub.2 and LiMn.sub.2O.sub.4; these lithium-containing
transition metal composite oxides wherein a plurality of transition
metals such as Co, Mn and Ni are mixed; these lithium-containing
transition metal composite oxides wherein a part of transition
metals is replaced by a metal other than transition metals;
phosphoric acid compounds of a transition metals such as
LiFePO.sub.4, LiCoPO.sub.4 or LiMnPO.sub.4 called olivine; oxides
such as TiO.sub.2, V.sub.2O.sub.5 or MoO.sub.3; sulfides such as
TiS.sub.2 or FeS; and conductive polymers such as polyacetylene,
polyparaphenylene, polyaniline, or polypyrrole; activated carbon;
polymers which generate a radical; carbon materials and the like
are used as a positive electrode material.
[0099] Acetylene black, ketjen black, carbon fibers or graphite as
a conducting material, and polytetrafluoroethylene, polyvinylidene
fluoride or SBR resin as a binding agent and the like are added to
positive electrode materials and negative electrode materials, and
moreover an electrode sheet molded in a sheet form may be used.
[0100] As a separator to prevent the contact of the positive
electrode and negative electrode, polypropylene, polyethylene,
paper, nonwoven fabric formed from e.g. glass fibers, or a porous
sheet is used.
[0101] An electrochemical device in the form of e.g. coin,
cylinder, square or aluminum laminate sheet is assembled from the
above elements.
EXAMPLES
[0102] The present invention will now be described in more detail
by way of examples. The scope of the present invention is not
limited to these examples in any way.
Synthesis Example 1: Synthesis of Compound (1a)
[0103] To a 50 ml eggplant flask, 7.0 g of EMC and 0.07 g of water
were added, and 1.00 g of fluorosulfonyl isocyanate was slowly
added thereto. After completion of foaming, 0.07 g of lithium
hydride was added, and the resultant mixture was stirred overnight.
The reaction liquid was filtered to obtain 7.8 g of an EMC solution
in which a target substance is dissolved at 14.7 mass % (target
substance 0.8 g, yield 86%).
Compound (1a):
[0104] .sup.19F-NMR [reference material; CFCl.sub.3, deuterated
solvent CD.sub.3CN], .delta. ppm; 50.46 (s, 2F).
[0105] .sup.13C-NMR [reference material; CD.sub.3CN, deuterated
solvent CD.sub.3CN], .delta. ppm; 166.36 (s, 1C).
[Preparation of Nonaqueous Electrolyte Solutions in Examples and
Comparative Examples]
Comparative Example 1-1
(Preparation of LiPF.sub.6 Solution)
[0106] In a glovebox at a dew point of -60.degree. C. or lower, EC,
FEC, EMC and DMC were mixed in a volume ratio of
EC:FEC:EMC:DMC=2:1:3:4. Subsequently, LiPF.sub.6 was added in an
amount to reach a concentration of 1.0 mol/L with respect to the
total amount of a nonaqueous electrolyte solution with the internal
temperature maintained at 40.degree. C. or lower, and completely
dissolved by stirring to obtain a LiPF.sub.6 solution. This was
used as comparative nonaqueous electrolyte solution 1-1.
Example 1-1
(Preparation of Nonaqueous Electrolyte Solution 1-1)
[0107] In a glovebox at a dew point of -60.degree. C. or lower, EC,
FEC, EMC and DMC were mixed in a volume ratio of
EC:FEC:EMC:DMC=2:1:3:4. Subsequently, LiPF.sub.6 was added in an
amount to reach a concentration of 1.0 mol/L with respect to the
total amount of a nonaqueous electrolyte solution with the internal
temperature maintained at 40.degree. C. or lower. Compound (1a)
corresponding to the compound represented by the general formula
(1) was added thereto at a concentration of 0.5 mass % with respect
to the total amount of the nonaqueous organic solvent, the solute
and the compound (1a) and was dissolved by stirring for an hour to
prepare nonaqueous electrolyte solution 1-1 in Example 1-1.
Examples 1-2 to 1-7 and Comparative Examples 1-2 to 1-5
(Preparation of Nonaqueous Electrolyte Solutions 1-2 to 1-7, and
Comparative Nonaqueous Electrolyte Solutions 1-2 to 1-5)
[0108] The nonaqueous electrolyte solutions 1-2 to 1-7 and
comparative nonaqueous electrolyte solutions 1-2 to 1-5 were
prepared in the same manner as in the preparation of nonaqueous
electrolyte solution 1-1, except that the type and amount added of
each of the compounds represented by the general formula (1) (and
comparative compounds) were changed as shown in Table 1.
Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3
(Preparation of Nonaqueous Electrolyte Solutions 2-1 to 2-3 and
Comparative Nonaqueous Electrolyte Solutions 2-1 to 2-3)
[0109] The nonaqueous electrolyte solutions 2-1 to 2-3 and
comparative nonaqueous electrolyte solutions 2-1 to 2-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 1-2, 1-5 and 1-7, and comparative nonaqueous
electrolyte solutions 1-1, 1-3 and 1-5, except that vinylene
carbonate was further added as the other additives so that the
concentration is set as shown in Table 2 with respect to the total
amount of the nonaqueous electrolyte solution.
Examples 3-1 to 3-3 and Comparative Examples 3-1 to 3-3
(Preparation of Nonaqueous Electrolyte Solutions 3-1 to 3-3 and
Comparative Nonaqueous Electrolyte Solutions 3-1 to 3-3)
[0110] The nonaqueous electrolyte solutions 3-1 to 3-3 and
comparative nonaqueous electrolyte solutions 3-1 to 3-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 2-1 to 2-3 and comparative nonaqueous
electrolyte solutions 2-1 to 2-3, except that vinylene carbonate
was changed to lithium bis(oxalato)borate.
Examples 4-1 to 4-3 and Comparative Examples 4-1 to 4-3
(Preparation of Nonaqueous Electrolyte Solutions 4-1 to 4-3 and
Comparative Nonaqueous Electrolyte Solutions 4-1 to 4-3)
[0111] The nonaqueous electrolyte solutions 4-1 to 4-3 and
comparative nonaqueous electrolyte solutions 4-1 to 4-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 2-1 to 2-3 and comparative nonaqueous
electrolyte solutions 2-1 to 2-3, except that vinylene carbonate
was changed to lithium difluoro(oxalato)borate.
Examples 5-1 to 5-3 and Comparative Examples 5-1 to 5-3
(Preparation of Nonaqueous Electrolyte Solutions 5-1 to 5-3 and
Comparative Nonaqueous Electrolyte Solutions 5-1 to 5-3)
[0112] The nonaqueous electrolyte solutions 5-1 to 5-3 and
comparative nonaqueous electrolyte solutions 5-1 to 5-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 2-1 to 2-3 and comparative nonaqueous
electrolyte solutions 2-1 to 2-3, except that vinylene carbonate
was changed to lithium difluorobis(oxalato)phosphate.
Examples 6-1 to 6-3 and Comparative Examples 6-1 to 6-3
(Preparation of Nonaqueous Electrolyte Solutions 6-1 to 6-3 and
Comparative Nonaqueous Electrolyte Solutions 6-1 to 6-3)
[0113] The nonaqueous electrolyte solutions 6-1 to 6-3 and
comparative nonaqueous electrolyte solutions 6-1 to 6-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 2-1 to 2-3 and comparative nonaqueous
electrolyte solutions 2-1 to 2-3, except that vinylene carbonate
was changed to lithium tetrafluoro(oxalato)phosphate.
Examples 7-1 to 7-3 and Comparative Examples 7-1 to 7-3
(Preparation of Nonaqueous Electrolyte Solutions 7-1 to 7-3 and
Comparative Nonaqueous Electrolyte Solutions 7-1 to 7-3)
[0114] The nonaqueous electrolyte solutions 7-1 to 7-3 and
comparative nonaqueous electrolyte solutions 7-1 to 7-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 2-1 to 2-3 and comparative nonaqueous
electrolyte solutions 2-1 to 2-3, except that vinylene carbonate
was changed to lithium bis(fluorosulfonyl)imide.
Examples 8-1 to 8-3 and Comparative Examples 8-1 to 8-3
(Preparation of Nonaqueous Electrolyte Solutions 8-1 to 8-3 and
Comparative Nonaqueous Electrolyte Solutions 8-1 to 8-3)
[0115] The nonaqueous electrolyte solutions 8-1 to 8-3 and
comparative nonaqueous electrolyte solutions 8-1 to 8-3 were each
prepared in the same manner as in the preparation of the nonaqueous
electrolyte solutions 2-1 to 2-3 and comparative nonaqueous
electrolyte solutions 2-1 to 2-3, except that vinylene carbonate
was changed to 1,3-propenesultone.
[0116] In the following Tables 1 to 8, DFP means lithium
difluorophosphate, FS means lithium fluorosulfonate, VC means
vinylene carbonate, BOB means lithium bis(oxalato)borate, DFOB
means lithium difluoro(oxalato) borate, DFBOP means lithium
difluorobis(oxalato)phosphate, TFOP means lithium
tetrafluoro(oxalato)phosphate, FSI means lithium
bis(fluorosulfonyl)imide and PRS means 1,3-propenesultone.
[0117] In the following Tables 1 to 8, the added amount of the
compound represented by the general formula (1) (and comparative
compounds DFP and FS) indicates a concentration with respect to the
total amount of a nonaqueous solvent, a solute, and such compound.
In addition, the added amount of other additives indicates a
concentration with respect to the total amount of a nonaqueous
solvent, a solute, such compound and such other additives.
[Production of Nonaqueous Electrolyte Battery]
(Production of NCM622 Positive Electrode)
[0118] In 90 mass % of LiNi.sub.0.6Mn.sub.0.2Co.sub.0.2O.sub.2
powder, 5 mass % of polyvinylidene fluoride (hereinafter referred
to as PVDF) as a binder and 5 mass % of acetylene black as a
conducting material were mixed, and N-methyl-2-pyrrolidone was
further added thereto to prepare a positive electrode mixture
paste. This paste was applied onto both sides of aluminum foil
(A1085), which was dried and pressed and then punched out at a size
of 4 cm.times.5 cm to prepare a NCM622 positive electrode for
tests.
(Production of Artificial Graphite Negative Electrode)
[0119] Ninety mass % of artificial graphite powder, 5 mass % of
PVDF as a binder and 5 mass % of acetylene black as a conducting
material were mixed to prepare a negative electrode mixture paste.
This paste was applied onto one surface of copper foil, which was
dried and pressed and then punched out at a size of 4 cm.times.5 cm
to prepare an artificial graphite negative electrode for tests.
(Production of Nonaqueous Electrolyte Batteries)
[0120] A terminal was welded to the above-described NCM622 positive
electrode under an argon atmosphere at a dew point of -50.degree.
C. or lower, and both sides thereof were then put between two
polyethylene separators (5 cm.times.6 cm). Furthermore, the
outsides thereof were put between two artificial graphite negative
electrodes to which terminals had been welded in advance so that
the surface of the negative electrode active material faces
opposite to the surface of the positive electrode active material.
They are put in an aluminum laminate bag having one opening left
and the nonaqueous electrolyte solution was vacuum filled therein.
After that, the opening was sealed with heat to produce an aluminum
laminate-type nonaqueous electrolyte battery in each of Examples
and Comparative Examples. The nonaqueous electrolyte solutions used
are those described in Tables 1 to 8.
[Evaluation]
--Initial Charge and Discharge--
[0121] A nonaqueous electrolyte battery was put in a 25.degree. C.
constant temperature bath and, in this state, connected to a
charge/discharge device. Charge was performed at 3 mA until 4.3 V.
After 4.3 V was maintained for an hour, discharge was performed at
6 mA until 3.0 V. This was one charge and discharge cycle, and 3
cycles in total of charge and discharge were performed to stabilize
the buttery.
<Measurement of Initial Resistance>
[0122] After the initial charge and discharge, the battery was
charged at 25.degree. C. and 6 mA until 4.3 V, and a resistance
value was directly measured by impedance determination.
[0123] In each of Tables 1 to 8, the initial resistance value of
Comparative Example using a comparative nonaqueous electrolyte
solution to which neither a compound represented by the general
formula (1) nor a comparative compound had been added (Comparative
Example 1-1 in Table 1, Comparative Example 2-1 in Table 2,
Comparative Example 3-1 in Table 3, Comparative Example 4-1 in
Table 4, Comparative Example 5-1 in Table 5, Comparative Example
6-1 in Table 6, Comparative Example 7-1 in Table 7, Comparative
Example 8-1 in Table 8) was used as 100, and the evaluation result
of the initial resistance in each of Examples and Comparative
Examples was shown as a relative value.
TABLE-US-00001 TABLE 1 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 1-1 Nonaqueous (1a) 0.5 -- -- 70.1 electrolyte
solution 1-1 Example 1-2 Nonaqueous (1a) 1.0 -- -- 64.9 electrolyte
solution 1-2 Example 1-3 Nonaqueous (1e) 0.3 -- -- 83.6 electrolyte
solution 1-3 Example 1-4 Nonaqueous (1e) 0.5 -- -- 82.6 electrolyte
solution 1-4 Example 1-5 Nonaqueous (1e) 1.0 -- -- 78.6 electrolyte
solution 1-5 Example 1-6 Nonaqueous (1w) 0.5 -- -- 82.3 electrolyte
solution 1-6 Example 1-7 Nonaqueous (1w) 1.0 -- -- 78.3 electrolyte
solution 1-7 Comparative Comparative nonaqueous -- -- -- -- 100
Example 1-1 electrolyte solution 1-1 Comparative Comparative
nonaqueous DFP 0.5 -- -- 87.6 Example 1-2 electrolyte solution 1-2
Comparative Comparative nonaqueous DFP 1.0 -- -- 85.3 Example 1-3
electrolyte solution 1-3 Comparative Comparative nonaqueous FS 0.5
-- -- 90.8 Example 1-4 electrolyte solution 1-4 Comparative
Comparative nonaqueous FS 1.0 -- -- 87.7 Example 1-5 electrolyte
solution 1-5
TABLE-US-00002 TABLE 2 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 2-1 Nonaqueous (1a) 1.0 VC 1.0 67.2 electrolyte
solution 2-1 Example 2-2 Nonaqueous (1e) 1.0 VC 1.0 83.4
electrolyte solution 2-2 Example 2-3 Nonaqueous (1w) 1.0 VC 1.0
83.2 electrolyte solution 2-3 Comparative Comparative nonaqueous --
-- VC 1.0 100 Example 2-1 electrolyte solution 2-1 Comparative
Comparative nonaqueous DFP 1.0 VC 1.0 88.2 Example 2-2 electrolyte
solution 2- 2 Comparative Comparative nonaqueous FS 1.0 VC 1.0 90.7
Example 2-3 electrolyte solution 2-3
TABLE-US-00003 TABLE 3 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 3-1 Nonaqueous (1a) 1.0 BOB 1.0 64.9 electrolyte
solution 3-1 Example 3-2 Nonaqueous (1e) 1.0 BOB 1.0 66.3
electrolyte solution 3-2 Example 3-3 Nonaqueous (1w) 1.0 BOB 1.0
66.2 electrolyte solution 3-3 Comparative Comparative nonaqueous --
-- BOB 1.0 100 Example 3-1 electrolyte solution 3-1 Comparative
Comparative nonaqueous DFP 1.0 BOB 1.0 88.8 Example 3-2 electrolyte
solution 3-2 Comparative Comparative nonaqueous FS 1.0 BOB 1.0 91.2
Example 3-3 electrolyte solution 3-3
TABLE-US-00004 TABLE 4 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 4-1 Nonaqueous (1a) 1.0 DFOB 1.0 56.4 electrolyte
solution 4-1 Example 4-2 Nonaqueous (1e) 1.0 DFOB 1.0 68.8
electrolyte solution 4-2 Example 4-3 Nonaqueous (1w) 1.0 DFOB 1.0
68.6 electrolyte solution 4-3 Comparative Comparative nonaqueous --
-- DFOB 1.0 100 Example 4-1 electrolyte solution 4-1 Comparative
Comparative nonaqueous DFP 1.0 DFOB 1.0 74.7 Example 4-2
electrolyte solution 4-2 Comparative Comparative nonaqueous FS 1.0
DFOB 1.0 76.8 Example 4-3 electrolyte solution 4-3
TABLE-US-00005 TABLE 5 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 5-1 Nonaqueous (1a) 1.0 DFBOP 1.0 64.5 electrolyte
solution 5-1 Example 5-2 Nonaqueous (1e) 1.0 DFBOP 1.0 80.7
electrolyte solution 5-2 Example 5-3 Nonaqueous (1w) 1.0 DFBOP 1.0
80.3 electrolyte solution 5-3 Comparative Comparative nonaqueous --
-- DFBOP 1.0 100 Example 5-1 electrolyte solution 5-1 Comparative
Comparative nonaqueous DFP 1.0 DFBOP 1.0 87.9 Example 5-2
electrolyte solution 5-2 Comparative Comparative nonaqueous FS 1.0
DFBOP 1.0 90.4 Example 5-3 electrolyte solution 5-3
TABLE-US-00006 TABLE 6 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 6-1 Nonaqueous (1a) 1.0 TFOP 1.0 66.2 electrolyte
solution 6-1 Example 6-2 Nonaqueous (1e) 1.0 TFOP 1.0 79.6
electrolyte solution 6-2 Example 6-3 Nonaqueous (1w) 1.0 TFOP 1.0
79.2 electrolyte solution 6-3 Comparative Comparative nonaqueous --
-- TFOP 1.0 100 Example 6-1 electrolyte solution 6-1 Comparative
Comparative nonaqueous DFP 1.0 TFOP 1.0 87.0 Example 6-2
electrolyte solution 6-2 Comparative Comparative nonaqueous FS 1.0
TFOP 1.0 90.1 Example 6-3 electrolyte solution 6-3
TABLE-US-00007 TABLE 7 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 7-1 Nonaqueous (1a) 1.0 FSI 1.0 65.0 electrolyte
solution 7-1 Example 7-2 Nonaqueous (1e) 1.0 FSI 1.0 82.9
electrolyte solution 7-2 Example 7-3 Nonaqueous (1w) 1.0 FSI 1.0
82.6 electrolyte solution 7-3 Comparative Comparative nonaqueous --
-- FSI 1.0 100 Example 7-1 electrolyte solution 7-1 Comparative
Comparative nonaqueous DFP 1.0 FSI 1.0 85.2 Example 7-2 electrolyte
solution 7-2 Comparative Comparative nonaqueous FS 1.0 FSI 1.0 87.7
Example 7-3 electrolyte solution 7-3
TABLE-US-00008 TABLE 8 Compound represented by general formula (1)
Other additives Initial Added Added resistance Nonaqueous amount
amount (relative electrolyte solution Type [mass %] Type [mass %]
value) Example 8-1 Nonaqueous (1a) 1.0 PRS 1.0 68.7 electrolyte
solution 8-1 Example 8-2 Nonaqueous (1e) 1.0 PRS 1.0 82.7
electrolyte solution 8-2 Example 8-3 Nonaqueous (1w) 1.0 PRS 1.0
82.5 electrolyte solution 8-3 Comparative Comparative nonaqueous --
-- PRS 1.0 100 Example 8-1 electrolyte solution 8-1 Comparative
Comparative nonaqueous DFP 1.0 PRS 1.0 86.8 Example 8-2 electrolyte
solution 8-2 Comparative Comparative nonaqueous FS 1.0 PRS 1.0 87.8
Example 8-3 electrolyte solution 8-3
[0124] As seen from Tables 1 to 8, it is found that a nonaqueous
electrolyte battery comprising a nonaqueous electrolyte solution
including a compound represented by the general formula (1) has low
initial resistance and thus is excellent.
* * * * *